Staging: rspiusb: Check usb_buffer_map_sg() retval

usb_buffer_map_sg() may return -1, check this directly.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Reviewed-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/rspiusb/rspiusb.c b/drivers/staging/rspiusb/rspiusb.c
index 04e2f92c0f6293292d55d5a56822a936d0a4ba52..0495fbfe59d9b47c44eb574d623fda64733ce3e6 100644 (file)
--- a/drivers/staging/rspiusb/rspiusb.c
+++ b/drivers/staging/rspiusb/rspiusb.c
@@ -611,6 +611,7 @@ static int MapUserBuffer(struct ioctl_struct *io, struct device_extension *pdx)
        int i = 0;
        int k = 0;
        int err = 0;
+       int ret;
        struct page **maplist_p;
        int numPagesRequired;
 
@@ -687,9 +688,16 @@ static int MapUserBuffer(struct ioctl_struct *io, struct device_extension *pdx)
        } else {
                pdx->sgl[frameInfo][0].length = count;
        }
-       pdx->sgEntries[frameInfo] =
-           usb_buffer_map_sg(pdx->udev, epAddr, pdx->sgl[frameInfo],
-                             pdx->maplist_numPagesMapped[frameInfo]);
+       ret = usb_buffer_map_sg(pdx->udev, epAddr, pdx->sgl[frameInfo],
+                       pdx->maplist_numPagesMapped[frameInfo]);
+       if (ret < 0) {
+               vfree(maplist_p);
+               dbg("usb_buffer_map_sg() failed");
+               return -EINVAL;
+       }
+
+       pdx->sgEntries[frameInfo] = ret;
+
        dbg("number of sgEntries = %d", pdx->sgEntries[frameInfo]);
        pdx->userBufMapped = 1;
        vfree(maplist_p);
@@ -716,8 +724,6 @@ static int MapUserBuffer(struct ioctl_struct *io, struct device_extension *pdx)
                pdx->PixelUrb[frameInfo][i]->transfer_flags =
                    URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT;
        }
-       if (i == 0)
-               return -EINVAL;
        /* only interrupt when last URB completes */
        pdx->PixelUrb[frameInfo][--i]->transfer_flags &= ~URB_NO_INTERRUPT;
        pdx->pendedPixelUrbs[frameInfo] =